JPH06313055A - Production of surface-roughened polyimide film - Google Patents

Abstract

PURPOSE:To prepare a polyimide film subjected to surface roughening treatment while keeping the excellent physical properties, heat resistance, etc., essential to an aromatic polyimide film to a high level, excellent in slippage and adhesion and, therefore, applicable, e.g. to a film for FPC or a base film for a double layer film. CONSTITUTION:This method is to produce a surface-roughened polyimide film by mixing the first aromatic polyamic acid solution prepared from a two benzene ring-containing aromatic tetracarboxylic acid component and an aromatic diamine component with the second aromatic polyamic acid solution prepared from a one benzene ring-containing aromatic tetracarboxylic acid component and an aromatic diamine component so that the weight ratio of the aromatic polyamic acids may be 9:1 to 6:4, casting the resultant mixture for formation of film, imidating it and treating the imidated film with an alkaline solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention uses a solution in which two different kinds of aromatic polyamic acids are dissolved in an organic polar solvent, forms a film at a relatively low temperature, and heat-treats at a high temperature to form a polyimide film. The present invention relates to a method for producing a roughened polyimide film having a fine concave structure on the surface by etching with an alkaline solution.

Further, since the roughened polyimide film of the present invention has excellent slipperiness and adhesiveness,
It can be used for applications such as films for (flexible printed wiring boards) and base films for two layers.

[0003]

2. Description of the Related Art An aromatic polyimide film is usually formed by casting a solution of polyamic acid (polyimide precursor) or a polyimide solution on a support to form a thin film, drying the thin film, and peeling it from the support. After that, it can be produced by further heating at a high temperature.

However, the polyimide film produced by such a method has a drawback that it is difficult to be used as a tape-like material for various purposes because the surface is very smooth and the slipperiness is poor. Therefore, various film roughening techniques have been proposed so far.

As a conventional technique for roughening the surface of a polyimide film, JP-A-60-127523 and JP-A-61-161 are available.
Although a method of adding fine particles to a film has been proposed as seen in JP-A-246919 and JP-A-63-108038, the fine particles cause agglomeration and generate abnormal protrusions, resulting in uniform film surface. It was difficult to roughen the surface.

Japanese Unexamined Patent Publication (Kokai) No. 63-297038 discloses a method of applying a coating composition comprising an aromatic polyamic acid solution containing fine particles to at least one surface of a polyimide film. However, this method also has a problem that the fine particles are likely to agglomerate and the manufacturing process is difficult to control.

Japanese Unexamined Patent Publication No. 62-263230 discloses a method in which a polyimide film is heated to a glass transition temperature or higher in the heating and drying steps to form protrusions on the film surface. However, this method involves the risk of foaming inside the film and the possibility of deterioration of the film itself.

JP-A-1-110535 discloses a method of stretching a polyimide film to form a bark-like structure on the film surface and roughening the surface. However, in this method, it is necessary to incorporate the stretching step into the conventional film stretching step, and this step requires strict accuracy, the equipment is expensive, and the operation control of the film production is often difficult.

In addition to the above methods, as a method for roughening a film, in JP-A-60-154017, film raw materials dissolved in a solution are cast or coated on a rough surface support to remove the solvent. After that, a method of peeling the formed film from the support to roughen one surface of the film is proposed. However, in this method, the release step of peeling the film from the rough surface support is difficult, and continuous production of the roughened film is often difficult.

Japanese Unexamined Patent Publication (Kokai) No. 62-171187 discloses a method of roughening a film by wet plasting. However, this method also needs to incorporate the blasting process into the conventional film manufacturing process,
It is possible that the manufacturing cost will increase.

A film surface roughening technique by etching has also been proposed, and Japanese Patent Application Laid-Open No. 3-60094 discloses a method for surface roughening a polyimide film using an alkaline treatment liquid. However, some problems have been raised in consideration of the technique related to etching of a polyimide film.

Conventionally, as a method of etching a polyimide film, there is a method of using a high-concentration alkaline aqueous solution or a hydrazine solution. However, since a polyimide film is generally rich in alkali resistance, even a high-concentration alkaline aqueous solution can sufficiently etch under normal conditions. Often not. Therefore, it takes a long time to perform sufficient surface roughening, but the alkaline aqueous solution penetrates into the polyimide film,
The polyimide film may swell.

[0013]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aromatic polyimide film having a roughened surface while maintaining the excellent physical properties and heat resistance originally possessed by the aromatic polyimide. To provide a manufacturing method of.

[0014]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present invention has been completed. This invention
A first aromatic polyamic acid solution obtained from an aromatic tetracarboxylic acid component having two benzene rings and an aromatic diamine component, an aromatic tetracarboxylic acid component having one benzene ring and an aromatic diamine component The second aromatic polyamic acid solution obtained from the above was mixed at a ratio of the aromatic polyamic acid in a weight ratio of 9: 1 to 6: 4, and the film imidized in a cast / thin film form was mixed with an alkaline solution. And a method for producing a roughened polyimide film. The first aromatic polyimide and the second aromatic polyimide have different solubilities in an alkaline solution, and the treatment with the alkaline solution selectively dissolves the second aromatic polyimide to form a fine concave structure on the surface. The present invention relates to a method for producing a roughened polyimide film, which is characterized by being formed.

The above-mentioned first aromatic polyimide or aromatic polyamic acid in the present invention is obtained from an aromatic tetracarboxylic acid component having two Bessen rings and an aromatic diamine component, and has two benzene rings. The aromatic tetracarboxylic acid component has 3,3 ′,
4,4'-biphenyltetracarboxylic acid, 2,3
3 ', 4'-biphenyltetracarboxylic acid, their acid dianhydrides, lower alcohol esterification products of these acids, such as 3,3', 4,4'-benzophenone tetracarboxylic acid or its acid dianhydride , Screw (3,
4-dicarboxyphenyl) methane or its acid dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane or its acid dianhydride, bis (3,4-dicarboxyphenylthioether or its acid dianhydride An anhydride, bis (3,4-dicarboxyphenyl) sulfone or an acid dianhydride thereof, or a mixture thereof can be used.

As the aromatic diamine component, phenylene-based diamine compounds such as m-phenylenediamine and p-phenylenediamine, benzidine-based compounds such as benzidine, 3,3'-dimethylbenzidine and 3,3'-dimethoxybenzidine, and 4 , 4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone and other benzophenone-based diamine compounds, 4,4'-diaminodiphenyl ether, 3,
Diphenyl ether type diamine compounds such as 3′-diaminodiphenyl ether, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 2,
2-bis (3-aminophenyl) propane, 3,3'-
Diphenyldiamine compounds such as diaminodiphenylmethane and 2,2-bis (3-aminophenyl) propane, 1,3-bis (4-aminophenoxy) benzene, and 1,4-bis (4-aminophenoxy) benzene. Bis (phenoxy) benzene-based diamine compound,
2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-
Aminophenoxy) phenyl] propane, bis (phenoxyphenyl) propane-based diamine compounds such as 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane, 4,4′-diaminodiphenylsulfone, 3,3 Diphenyl sulfone-based diamine compounds such as'-diaminodiphenyl sulfone, 3,7-diaminodiphenylene sulfone, 2,8-dimethyl-
Diphenylene sulfone-based diamine compounds such as 3,7-diaminodiphenylene sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3
Examples thereof include aromatic diamine components containing mainly (90 mol% or more) bis (phenoxyphenyl) sulfone-based diamine compounds such as -aminophenoxy) phenyl] sulfone.

As the aromatic tetracarboxylic acid component having two benzene rings in the present invention, 3,3 ',
4,4'-biphenyltetracarboxylic acid, 2,3
3 ', 4'-biphenyltetracarboxylic acid, or an acid dianhydride or ester thereof is preferable, and as the aromatic diamine component, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'- Aromatic polyimides from which diaminodiphenyl ether can be obtained are preferred from the viewpoint of alkali resistance.

The second aromatic polyimide or aromatic polyamic acid in the present invention is pyromellitic acid or an acid anhydride thereof as the aromatic tetracarboxylic acid component, and the aromatic aromatic diamine component as described above. It consists of a diamine compound.

The organic polar solvent used in the film forming solution and the like in the production method of the present invention may be any one as long as it can uniformly dissolve the first and second aromatic polyamic acids. N, N-dimethylacetamide, N, N
-Diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide and the like, N, N-di-lower alkylcarboxylamides, N-methyl-2-
Pyrrolidone, dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, diethyl sulfone, hexamethyl sulfamide and the like can be mentioned.

In the method for producing each aromatic polyamic acid used in the production method of the present invention, the above-mentioned aromatic tetracarboxylic acid component and aromatic diamine component are used in substantially equimolar amounts in the above-mentioned organic polar solvent. Then, a method of polymerizing at a temperature of about 100 ° C. or lower, particularly 60 ° C. or lower to produce an aromatic polyamic acid can be mentioned. The ratio of the two components used does not necessarily have to be completely equimolar, and if one of the components is within 10 mol% with respect to the other components, particularly within 5 mol%, it is used in excess. It may have been done.

The preparation of the film-forming aromatic polyamic acid solution used in the present invention is carried out, for example, by first separately preparing a solution of the first aromatic polyamic acid in an organic polar solvent and a solution of the second aromatic polyamic acid. An organic polar solvent solution is prepared and prepared, and each of the aromatic polyamic acid solutions is prepared at a temperature of 0 to 100 ° C., particularly 0 to 80 ° C., and more preferably 0 to 70 ° C. It is preferable to mix for 2 to 50 hours.

In preparing the solution for film formation of the present invention,
Unless each aromatic polyamic acid solution is mixed under a temperature condition of 100 ° C. or lower, preferably 70 ° C. or lower,
Dissociation of the molecular chains of each aromatic polyamic acid in the mixed solution,
And repolymerization is likely to occur actively at the same time, as a result, a polyamic acid copolymer composed of all monomers dissociated from each aromatic polyamic acid is generated, and a solution containing such a copolymer is formed into a film. It is not preferable to use it because it does not form a fine concave shape on the surface even when treated with an alkaline solution.

The organic polar solvent of the first aromatic polyamic acid solution of the present invention and the organic polar solvent of the second aromatic polyamic acid solution may be the same solvent or substantially the same solvent. , The ease of mixing the above solutions,
It is preferable from the viewpoint of ease of solvent recovery.

In the present invention, after preparing an aromatic polyamic acid solution for film formation, the solution for film formation is then formed into a thin film on a support, and the temperature is 130 ° C. or lower, preferably 10 to
Dry at a temperature of 100 ° C. to form a self-supporting film. When the drying is performed at a temperature higher than 130 ° C., when the thin film becomes a self-supporting film, a copolymer is produced similarly to the preparation of the film-forming solution, which is not suitable.

The formation of the self-supporting film in the present invention is performed, for example, by continuously extruding an aromatic polyamic acid solution for film formation through a slit die into a thin film, and rotating the thin film on a belt or a drum. Place the film on the surface and cast it to form a thin film of uniform thickness.
It can be carried out by a method of continuously forming a film-shaped self-support by drying at a temperature of 0 ° C. or lower.

The obtained film-like self-supporting body was heated at 300 ° C.
The film is heated to the above temperature and imidized to obtain a polyimide film. The polyimide film thus obtained is treated with an alkaline solution to form a fine concave structure on the surface of the film.

As the alkaline solution, an inorganic base such as sodium hydroxide or potassium hydroxide, propylamine,
Organic bases such as ethylenediamine and hydrazine, alone or in a mixture, with water, alcohol solvents such as methanol and ethanol, N, N-dimethylacetamide,
An alkaline solution using an amide solvent such as N, N-diethylacetamide or N, N-dimethylformamide can be preferably mentioned.

The aromatic polyimide film of the present invention comprises
The second aromatic polyimide is finely dispersed in the first aromatic polyimide film. Solubility by the alkaline solution is different between the first aromatic polyimide and the second aromatic polyimide, and the second aromatic polyimide has better solubility in the alkaline solution. The second aromatic polyimide present in the film is selectively dissolved to form a crater-like concave structure on the film surface. The temperature of the treatment with the alkaline solution is 10 to 100 ° C, preferably 20 to 100 ° C. The processing time is 10 seconds to 5 hours.

[0029]

EXAMPLES Examples and comparative examples will be shown below. Example 1 A) 29.42 g of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and p-phenylenediamine 1
0.81 g was polymerized with 362.1 g of N, N-dimethylacetamide solvent at 25 ° C. for 4 hours to obtain a reaction solution of a first aromatic polyamic acid [polymer concentration;
10% by weight, solution viscosity at 25 ° C .; 500 poise (solution viscosity measured by a rotary viscometer)] 80 g was collected. B) 21.81 g of pyromellitic dianhydride and 4,4 '
-Diaminodiphenyl ether 20.02 g and 37
2 in 6.5 g of N, N-dimethylacetamide solvent
Second aromatic polyamic acid reaction solution obtained by polymerization at 5 ° C. for 4 hours [polymer concentration: 10% by weight, 25 ° C.
Solution concentration: 300 poise (same as above)] 20 g. After mixing A and B at 25 ° C. and further stirring at room temperature for 8 hours to prepare a mixed solution, the solution for film formation was cast evenly on a glass plate, and the solution was blown with hot air at 60 ° C. for 20 hours. By heating for a minute, a long self-supporting film (solvent content: 48% by weight) was formed.

The self-supporting film was heated at 200 ° C. for 10 minutes.
After that, heat treatment was performed for 5 minutes at 400 ° C. for 5 minutes to produce an aromatic polyimide film. The obtained polyimide film was immersed in 80% hydrazine hydrate and treated at 25 ° C for 1 hour. A scanning electron micrograph of the surface of the aromatic polyimide film is shown in FIG. As shown in FIG. 1, many fine concave structures are formed on the film surface.

Comparative Example 1 Similar to A of Example 1, an aromatic polyamic acid solution obtained from 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride and P-phenylenediamine (solvent; N, N
-Dimethylacetamide, viscosity: 500 poise) was cast into a glass plate to produce an aromatic polyimide film. The obtained polyimide film is 80% hydrazine-
It was immersed in a hydrate and treated at 25 ° C. for 1 hour. A scanning electron micrograph of the surface of this polyimide film is shown in FIG. No fine concave structure was formed on the surface of this film.

[0032]

The present invention provides a first aromatic polyimide obtained from an aromatic tetracarboxylic acid component having two benzene rings and an aromatic diamine component, and an aromatic tetracarboxylic acid having one benzene ring. A homogeneous mixed film of a second aromatic polyimide obtained from a component and an aromatic diamine component, wherein the first aromatic polyimide and the second aromatic polyimide have different solubilities in an alkaline solution. The present invention relates to a method for producing a roughened polyimide film, characterized in that the second aromatic polyimide is selectively dissolved by the treatment with to form a fine concave structure on the surface. By using the production method of the present invention, it is possible to provide a roughened polyimide film while maintaining the excellent physical properties and heat resistance originally possessed by the aromatic polyimide film at a high level. Further, since the roughened polyimide film of the present invention has excellent slipperiness and adhesiveness, it can be used as a film for FPC or a base film for two layers.

[0033]

[Brief description of drawings]

FIG. 1 is a scanning electron micrograph of an aromatic polyimide film obtained in Example 1 according to the present invention and having a roughened surface and a fine concave structure.

FIG. 2 is a scanning electron micrograph of a non-roughened aromatic polyimide film obtained in Comparative Example 1 according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location H01L 21/306 9272-4M

Claims (1)

[Claims] 1. A first aromatic polyamic acid solution obtained from an aromatic tetracarboxylic acid component having two benzene rings and an aromatic diamine component, and an aromatic tetracarboxylic acid component having one benzene ring. The second aromatic polyamic acid solution obtained from the aromatic diamine component is mixed at a weight ratio of the aromatic polyamic acid of 9: 1 to 6: 4, and is cast into a thin film to be imidized. A method for producing a roughened polyimide film, which comprises treating the formed film with an alkaline solution.